Modified polyacrylonitrile-based activated carbon fibers applied in supercapacitor

2016 ◽  
Vol 45 (3) ◽  
pp. 164-171 ◽  
Author(s):  
Linjie Su ◽  
Bohong Li ◽  
Dongyu Zhao ◽  
Chuanli Qin ◽  
Zheng Jin
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Electrode Material ◽  
High Specific Capacitance ◽  
Activated Carbon Fibers ◽  
Content Type

Purpose The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor. Design/methodology/approach In this study, the specific capacitance of ACF was significantly increased by using the phenolic resin microspheres and melamine as modifiers to prepare modified PAN-based activated carbon fibers (MACFs) via electrospinning, pre-oxidation and carbonization. The symmetrical supercapacitor (using MACF as electrode) and hybrid supercapacitor (using MACF and activated carbon as electrodes) were tested in term of electrochemical properties by cyclic voltammetry, AC impedance and cycle stability test. Findings It was found that the specific capacitance value of the modified fibers were increased to 167 Fg-1 by adding modifiers (i.e. 20 wt.% microspheres and 15 wt.% melamine) compared to that of unmodified fibers (86.17 Fg-1). Specific capacitance of modified electrode material had little degradation over 10,000 cycles. This result can be attributed to that the modifiers embedded into the fibers changed the original morphology and enhanced the specific surface area of the fibers. Originality/value The modified ACFs in our study had high specific surface area and significantly high specific capacitance, which can be applied as efficient and environmental absorbent, and advanced electrode material of supercapacitor.

Bead chain structure RFC/ACF by electrospinning for supercapacitors

2019 ◽  
Vol 48 (5) ◽  
pp. 439-448
Author(s):  
Lei Guo ◽  
Lien Zhu ◽  
Lei Ma ◽  
Jian Zhang ◽  
QiuYu Meng ◽  
...  
Keyword(s):  
Composite Material ◽  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
High Specific Capacitance ◽  
Chain Structure ◽  
Cycle Stability ◽  
Content Type

Purpose The purpose of this paper is to prepare a spherical modifier-modified activated carbon fiber of high specific capacitance intended for electrode materials of supercapacitor. Design/methodology/approach In this study, phenolic-based microspheres are taken as modifiers to prepare PAN-based fiber composites by electrospinning, pre-oxidation and carbonization. Pearl-chain structures appear in RFC/ACF composites, and pure polyacrylonitrile fibers show a dense network. The shape and cross-linking degree are large. After the addition of the phenolic-based microspheres, the composite material exhibits a layered pearlite chain structure with a large porosity, and the RFC/ACF composite material is derived because of the existence of a large number of bead chain structures in the composite material. The density increases, the volume declines and the mass after being assembled into a supercapacitor as a positive electrode material decreases. The specific surface area of RFC/ACF composites is increased as compared to pure fibers. The increase in specific surface area could facilitate the diffusion of electrolyte ions in the material. Owing to the large number of bead chains, plenty of pore channels are provided for the diffusion of electrolyte ions, which is conducive to enhancing the electrochemical performance of the composite and improving the RFC/ACF composite and the specific capacitance of the material. The methods of electrochemical testing on symmetric supercapacitors (as positive electrodes) are three-electrode cyclic voltammetry, alternating current impedance and cycle stability. Findings The specific capacitance value of the composite material was found to be 389.2 F/g, and the specific capacitance of the electrode operating at a higher current density of 20 mA/cm2 was 11.87 F/g (the amount of the microsphere modifier added was 0.3 g). Using this material as a positive electrode to assemble into asymmetrical supercapacitor, after 2,000 cycles, the specific capacitance retention rate was 87.46 per cent, indicating excellent cycle stability performance. This result can be attributed to the fact that the modifier embedded in the fiber changes the porosity between the fibers, while improving the utilization of the carbon fibers and making it easier for electrolyte ions to enter the interior of the composites, thereby increasing the capacitance of the composites. Originality/value The modified PAN-based activated carbon fibers in the study had high specific surface area and significantly high specific capacitance, which makes it applicable as an efficient and environment-friendly absorbent, as well as an advanced electrode material for supercapacitor.

Fabrication of Activated Carbon Fibers from Stabilized PAN-Based Fibers by KOH

2004 ◽  
Vol 449-452 ◽  
pp. 217-220 ◽  
Author(s):  
Young Jae Lee ◽  
Jae Hyung Kim ◽  
Jang Soon Kim ◽  
Dong Bok Lee ◽  
Jae Chun Lee ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Potassium Hydroxide ◽  
Chemical Activation ◽  
Activated Carbon Fibers ◽  
High Concentration

Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using potassium hydroxide at different concentration. The experimental data showed variations in specific surface area, microstructure by the activated carbon fibers. Specific surface area of about 2545 m2/g was obtained in the KOH/stabilized PAN-based fiber ratio of 1:1 at 800°. An abrupt reduction of specific surface area was observed in the experiments with the ratio of 3:1 of OH/stabilized PAN-based fiber, being dissimilar with the result of KOH/fiber ratios of 1:1 and 2:1 in the similar experiments. The high concentration of KOH led to the destruction of micropore walls instead of forming mesopores.

scholarly journals Coconut-based activated carbon fibers for efficient adsorption of various organic dyes

RSC Advances ◽  
2018 ◽  
Vol 8 (74) ◽  
pp. 42280-42291 ◽  
Author(s):  
Ling Zhang ◽  
Ling-yu Tu ◽  
Yan Liang ◽  
Qi Chen ◽  
Ze-sheng Li ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Organic Dyes ◽  
Low Cost ◽  
Micropore Volume ◽  
Activated Carbon Fibers ◽  
Large Specific Surface Area

Activated carbon fibers with high micropore volume and large specific surface area were prepared from abundant and low-cost coconut fibers, which show excellent adsorption performances towards various dyes.

Preparation of Activated Carbon Fibers by Chemical Activation Method with Hydroxides

2006 ◽  
Vol 510-511 ◽  
pp. 750-753 ◽  
Author(s):  
Sook Young Moon ◽  
Myung Soo Kim ◽  
Hyun Sik Hahm ◽  
Yun Soo Lim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Chemical Activation ◽  
Lower Surface ◽  
Activation Process ◽  
Temperature Profiles ◽  
Activated Carbon Fibers

Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using hydroxides at different concentrations. The experimental data showed variations in specific surface area, microstructure, pore size distribution, and amounts of iodine adsorbed by the activated carbon fibers. Specific surface area of about 2244m2/g and iodine adsorption of 1202mg/g were obtained in the KOH 1.5M. However, the use of NaOH in the activation process rather than KOH and using the same time/ temperature profiles resulted in a carbon with a much lower surface area. KOH is a more developed pore structure than NaOH, which means that KOH is a better activation agent in producing ACF than NaOH.

Sustainable activated carbon fibers from liquefied wood with controllable porosity for high-performance supercapacitors

2014 ◽  
Vol 2 (30) ◽  
pp. 11706-11715 ◽  
Author(s):  
Zhi Jin ◽  
Xiaodong Yan ◽  
Yunhua Yu ◽  
Guangjie Zhao
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Surface Area ◽  
Carbon Fibers ◽  
High Performance ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
Activated Carbon Fibers ◽  
Micropore Surface Area ◽  
Liquefied Wood

The combination of the high micropore surface area and the controlled mesopore size and mesopore/micropore ratio is responsible for high specific capacitance and excellent rate capability.

scholarly journals Pitch-Derived Activated Carbon Fibers for Emission Control of Low-Concentration Hydrocarbon

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1313 ◽  
Author(s):  
Hye-Min Lee ◽  
Byeong-Hoon Lee ◽  
Soo-Jin Park ◽  
Kay-Hyeok An ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Volume Fraction ◽  
Structural Characteristics ◽  
Total Pore Volume ◽  
Activated Carbon Fibers

The unburned hydrocarbon (HC) emissions of automobiles are subject to strong regulations because they are known to be converted into fine dust, ozone, and photochemical smog. Pitch-based activated carbon fibers (ACF) prepared by steam activation can be a good solution for HC removal. The structural characteristics of ACF were observed using X-ray diffraction. The pore characteristics were investigated using N2/77K adsorption isotherms. The butane working capacity (BWC) was determined according to ASTM D5228. From the results, the specific surface area and total pore volume of the ACF were determined to be 840–2630 m2/g and 0.33–1.34 cm3/g, respectively. The butane activity and butane retentivity of the ACF increased with increasing activation time and were observed to range between 15.78–57.33% and 4.19–11.47%, respectively. This indicates that n-butane adsorption capacity could be a function not only of the specific surface area or total pore volume but also of the sub-mesopore volume fraction in the range of 2.0–2.5 nm of adsorbents. The ACF exhibit enhanced BWC, and especially adsorption velocity, compared to commercial products (granules and pellets), with lower concentrations of n-butane due to a uniformly well-developed pore structure open directly to the outer surface.

scholarly journals Characterization of Activated Carbon Fibers

1990 ◽  
Vol 209 ◽  
Author(s):  
A. W. P. Fung ◽  
A. M. Rao ◽  
K. Kuriyama ◽  
M. S. Dresselhaus ◽  
G. Dresseliiaus ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Disordered Systems ◽  
Activated Carbon Fibers ◽  
Characterization Of Activated Carbon

AbstractLow-temperature electrical conductivity and Raman scattering are studied as characterization tools for activated carbon fibers, which have a high density of defects and a huge specific surface area. The transport mechanism at low temperature is governed by variablerange hopping, as in other strongly disordered systems. From the Raman spectra obtained, we deduce that the long phenolic fibers are more disordered than the acrylic fibers and that increased specific surface area corresponds to increased disorder. The average in-plane microcrystallite size is about 20–30 Å.

scholarly journals Activated carbon fibers for toxic gas removal based on electrical investigation: Mechanistic study of p-type/n-type junction structures

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Byong Chol Bai ◽  
Young-Seak Lee ◽  
Ji Sun Im
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Chemical Activation ◽  
Mechanistic Study ◽  
Activated Carbon Fibers ◽  
Gas Removal ◽  
P Type

Abstract In this study, we evaluated the potential use of CuO-ZnO combination structures with activated carbon fibers (ACFs) for the adsorption (by ACFs) and electrochemical detection (by CuO-ZnO) by of SO2 gas. The gas adsorptivity was concluded to improve as a result of the synergetic effects of physical adsorption by the micropores and mesopores, the specific surface area developed by chemical activation and the chemical adsorption reaction between SO2 and the transition metals introduced in the CuO-ZnO combination structures. From comparison of the SO2 sensing properties, the CuO-ZnO combination structures with ACFs exhibited the fastest sensing capability. This result can be attributed to the larger specific surface area of the semiconductor, which extended its depletion layer by forming p-type CuO/n-type ZnO junctions. This phenomenon led to good SO2 detection through a decrease in the resistance; thus, the contributions of the sensing responses of p-type CuO and n-type ZnO represent a predominant characteristic of the sensor. These types of mechanisms were proven through various physicochemical and electrical characterization methods, especially through evaluation of the SO2 sensing capability of the CuO-ZnO combination structures with ACFs. The reversible sensing capability indicates that the p-n junction structure changed the electrical properties of the ACFs, leading to an intriguing sensing mechanism.

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